TOUCH DEVICE AND SENSING COMPENSATION METHOD
A touch device and a sensing compensation method are provided. The touch device may include a touch panel, a sensing compensation circuit and a sensing circuit. The sensing compensation circuit may be coupled to the touch panel for providing a compensation-impedance according to features of the touch panel. The sensing circuit may be coupled to the sensing compensation circuit. The sensing circuit receives touch information compensated by the sensing compensation circuit.
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This application claims the priority benefit of Taiwan application serial no. 102121990, filed on Jun. 20, 2013. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
TECHNICAL FIELDThe disclosure relates to a touch device and a sensing compensation method.
BACKGROUNDFollowing the vigorous development of smart phones and tablet computers, projected capacitive touch panels have gradually taken the places of the conditional keyboards and mice and become the major input interfaces. Either the projected capacitive touch panels with small sizes or those with large sizes have a delay issue resulted from parasitic resistance and parasitic capacitance. The delay issue caused by the parasitic resistance and the parasitic capacitance leads to signal bandwidth limitation. Overly large parasitic resistance and parasitic capacitance would leads to the reduction of the sensitivity for sensing change in mutual capacitance of touch units in the touch panel, and as a result, a signal-to-noise ratio (SNR) of a sensing signal may be decreased.
SUMMARYAn embodiment of the disclosure introduces a touch device. The touch device may include a touch panel, a sensing compensation circuit and a sensing circuit. The sensing compensation circuit is coupled to the touch panel and provides a compensation-impedance according to features of the touch panel. The sensing circuit is coupled to the sensing compensation circuit and receives touch information compensated by the sensing compensation circuit.
An embodiment of the disclosure introduces a sensing compensation method for a touch device. The method may include providing a touch panel, providing a compensation-impedance by a sensing compensation circuit according to features of the touch panel and receiving touch information by a sensing circuit, where in the touch information being may be compensated by the sensing compensation circuit.
Several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the disclosure.
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
The term “coupling/coupled” used in this specification (including claims) may refer to any direct or indirect connection means. For example, “a first device is coupled to a second device” may be interpreted as “the first device is directly connected to the second device” or “the first device is indirectly connected to the second device through other devices or connection means.” Moreover, wherever appropriate in the drawings and embodiments, elements/components/steps with the same reference numerals represent the same or similar parts. Elements/components/steps with the same reference numerals or names in different embodiments may be cross-referenced.
The touch panel 120 is disposed with one or more touch units (e.g. a touch unit 122) so as to sense whether a touch event occurs on the touch panel 120. According to different design requirements, the touch unit 122 may have various layout structure designs.
The touch panel 120 is disposed with one ore more drive lines. The driving circuit 110 may be coupled to a first electrode of the touch unit 122 through the drive line. The drive line has an impedance RITO1. The touch panel 120 may also be disposed with one ore more sense line. The second electrode of the touch unit 122 is coupled to the sense lines. The sense lines have an impedance RITO2. A sensing terminal of the sensing compensation circuit 130 is coupled to the sense lines of the touch panel 120 to sense touch information of the touch unit 122 in the touch panel 120. Based on different design requirements, the drive lines and the sense lines may be transparent conduction lines, semi-transparent conduction lines or non-transparent conduction lines. For instance, in the present exemplary embodiment, the drive lines and the sense lines may be implemented by utilizing ITO conduction lines.
In the sensing operation of the touch unit 122, the driving circuit 110 provides a driving signal Vdrive through the drive line to the first electrode of the touch unit 122, and the sensing compensation circuit 130 synchronously senses the touch information of the touch unit 122 using the sense lines. In the touch panel 120, the impedance RITO2 would possibly be increased due to an overly long length (and/or an overly thin line diameter) of a sense line, and time delay caused by the impedance RITO2 and the parasitic capacitance Cs2 would result in signal bandwidth limitation that can not be ignored.
In the present exemplary embodiment, the sensing terminal of the sensing compensation circuit 130 may provide a negative input impedance −Req. The negative input impedance −Req provided by the sensing compensation circuit 130 may compensate the impedance RITO2 of the sense lines in the touch panel 120 and may be determined according to actual product design requirements. For instance, an absolute value of the negative input impedance −Req (i.e., |−Req|) may be set to be within a certain impedance range defined according to the impedance RITO2 of the sense lines. For example, according to a design requirement, a tolerable error value ΔR may be determined, and the impedance range may be from RITO2−ΔR to RITO2+ΔR. In the present exemplary embodiment, the absolute value of the negative input impedance −Req may be equal to the impedance RITO2 of the sense lines.
Since the sensing compensation circuit 130 may provide the negative input impedance −Req, an impedance on a sensing path of the sensing compensation circuit 130 to the touch unit 122 is RITO2+(−Req). Therefore, the sensing compensation circuit 130 may offset/compensate the impedance of the sense line RITO2 in the touch panel 120 so as to lower the bandwidth limitation on sensing signals resulted from the impedance RITO2 and the parasitic capacitance Cs2 and increase a speed for sensing the touch panel 120. Moreover, by the negative input impedance −Req offsetting/compensating the impedance RITO2 of the sense lines, the sensitivity for the sensing compensation circuit 130 sensing change of a mutual capacitance Cm may be enhanced, and thereby a signal-to-noise ratio (SNR) of the sensing signal may be increased.
A result (i.e., an output signal Vout) for the sensing compensation circuit 130 sensing the sense line is sent to the sensing circuit 140. Based on different design requirements on products, the sensing circuit 140 may be designed and configured in various ways. For instance, in some exemplary embodiments, the sensing circuit 140 may be disposed with an integrator 141, an analog-to-digital converter 142 and a controller 143. The integrator 141 may receive the output signal Vout and correspondingly output an integration result to the analog-to-digital converter 142. The analog-to-digital converter 142 may convert an analog output from the integrator 141 into a digital code and sends the digital code to the controller 143. The controller 143 may check the digital code and determine whether a touch event occurs in the touch unit 122 according to the checking result. In other exemplary embodiments, the sensing circuit 140 is not limited thereto.
In the present exemplary embodiment, the negative impedance circuit 200 includes an amplifier 210, a first impedance 220, a second impedance 230 and a third impedance 240. In the present exemplary embodiment, a first input terminal of the amplifier 210 is an inverted input terminal, while a second input terminal of the amplifier 210 is a non-inverted input terminal. In other present exemplary embodiments, the first input terminal of the amplifier 210 is a non-inverted input terminal, while the second input terminal of the amplifier 210 is an inverted input terminal. The first input terminal of the amplifier 210 is coupled to the input terminal of the negative impedance circuit 200, and an output terminal of the amplifier 210 is coupled to the output terminal of the negative impedance circuit 200.
A first terminal and a second terminal of the first impedance 220 are respectively coupled to the first input terminal and the output terminal of the amplifier 210. A first terminal and a second terminal of the second impedance 230 are respectively coupled to the second input terminal and the output terminal of the amplifier 210. In the present exemplary embodiment, a first terminal and a second terminal of the third impedance 240 are respectively coupled to the second input terminal of the amplifier 210 and a reference voltage (e.g. a ground voltage or any other constant voltage). One of the first impedance 220, the second impedance 230 and the third impedance 240 is a first impedance unit. The first impedance unit comprises a resistor, a variable resistor, a capacitor, a variable capacitor, an inductor, a variable inductor or any other type of impedance. In the present exemplary embodiment, for example, the first impedance 220, the second impedance 230 and the third impedance 240 may be any type of resistors. In other present exemplary embodiments, the first impedance 220, the second impedance 230 and/or the third impedance 240 may be a capacitor, an inductor or any other impedance.
Given that the first impedance 220 has a resistance R1, the second impedance 230 has a resistance R2, the third impedance 240 has a resistance R3, while the amplifier 210 may be assumed as an ideal amplifier, them an equivalent input impedance Req of the negative impedance circuit 200 is calculated by an equation, Req=−(R1R3)/R2. When the equivalent input impedance Req of the negative impedance circuit 200 is identical to the impedance RITO2 of the sense lines, a sensing electrode (e.g. a node N2 shown in
Given that R1=RITO2, when a frequency ω of the driving signal Vdrive is quite high, a relationship between the output signal Vout of the sensing compensation circuit 130 and the driving signal Vdrive of the driving circuit 110 may be expressed by [Vout(jω)/Vdrive(jω)]=−{[jω*Cm*RITO2]/[1+jω(Cs1+Cm)RITO1]}*[1+(R2/R3)]≈−[Cm/(Cs1+Cm)]*(RITO2/RITO1)*(1+R2/R3). Since the touch device 100 is capable of eliminating/improving the impact of the impedance RITO2 of the sense lines, a bandwidth and a sensing speed of the sensing compensation circuit 130 may be increased. Moreover, by adjusting a ratio of R2 to R3 (e.g. setting R2>R3), a change value of the mutual capacitor Cm may be enlarged, and the impact from the impedance RITO2 of the sense lines may be eliminated. In addition, the touch device 100 may use the driving signal Vdrive having a lower voltage.
The touch panel 120 may be formed by a plurality of touch units 122 arranged in an array. First electrodes of the touch units 122 belonging to different columns are electrically connected to different lines respectively, while second electrodes of the touch units 122 belonging to different rows are electrically connected to different sense lines respectively. Alternatively, the first electrodes of the touch units 122 belonging to different rows are electrically connected to different drive lines respectively, while the second electrodes of the touch units 122 belonging to different columns are electrically connected to different sense lines respectively. Different sense lines may have different impedances RITO2. The touch units 122 at different positions on the same sense line also have different impedance RITO2. When the touch units 122 of the touch panel 120 is more, the number of resistance levels of the first impedance 420 is also more so as to offset/compensate the impedance RITO2 of the sense lines.
The variable resistor of the first impedance 420 illustrated in
The variable resistor of the first impedance 420 illustrated in
When the touch units 122 of the touch panel 120 are more, the number of resistance levels for the first impedance 420 becomes more. Thus, in order to save an area of an integrated circuit (IC), the reuse of the resistors has to be increased. In some exemplary embodiments, the reuse of the resistors may be increased by adjusting the configurations of the connection in series or in parallel of each resistor in the first impedance 420. For instance, the variable resistor of the first impedance 420 illustrated in
The controllable resistance unit 810 includes the resistor R11, a multiplexer MUX1 and a multiplexer MUX2. A first terminal of the resistor R11 is served as a first terminal of the controllable resistance unit 810, a common terminal of the multiplexer MUX1 is coupled to a second terminal of the resistor R11, and a first select terminal of the multiplexer MUX1 is served as a third terminal of the controllable resistance unit 810. A first select terminal of the multiplexer MUX2 is coupled to the first terminal of the resistor R11, a second select terminal of the multiplexer MUX2 is coupled to the second select terminal of the multiplexer MUX1, and a common terminal of the multiplexer MUX2 is served as the second terminal of the controllable resistance unit 810. Related descriptions of the controllable resistance units 820˜850 may be embodied with reference to the controllable resistance unit 810. For instance, the controllable resistance unit 820 includes the resistor R12, a multiplexer MUX3 and a multiplexer MUX4, the controllable resistance unit 830 includes the resistor R13, a multiplexer MUX5 and a multiplexer MUX6, the controllable resistance unit 840 includes the resistor R14, a multiplexer MUX7 and a multiplexer MUX8, and the controllable resistance unit 850 includes the resistor R15, a multiplexer MUX9 and a multiplexer MUX10. Each of the controllable resistance units 810˜850 utilizes, for example, a two-to-one multiplexer to switch between the configurations of the connection in series and the connection in parallel of each resistor.
The multiplexers MUX1˜MUX10 are respectively controlled by control signals A0, A1, A2, A3 and A4 of a controller 800. When the control signals A0˜A4 are equal to 0, the first input terminal of the amplifier 210 may be coupled to first terminals of the resistors R11˜R16 through the multiplexers MUX2, MUX4, MUX6, MUX8 and MUX10, and the output terminal of the amplifier 210 may be coupled to second terminals of the resistors R11˜R16 through the multiplexers MUX1, MUX3, MUX5, MUX7 and MUX9, wherein at this time, the coupling relationship among the resistors R11˜R16 are parallel.
When the control signals A0˜A4 are equal to 1, the second terminal of the resistor R11 is coupled to the first terminal of the resistor R12 through the multiplexer MUX1 and the multiplexer MUX2, the second terminal of the resistor R12 is coupled to the first terminal of the resistor R13 through the multiplexer MUX3 and the multiplexer MUX4, the second terminal of the resistor R13 is coupled to the first terminal of the resistor R14 through the multiplexer MUX5 and the multiplexer MUX6, the second terminal of the resistor R14 is coupled to the first terminal of the resistor R15 through the multiplexer MUX7 and the multiplexer MUX8, and the second terminal of the resistor R15 is coupled to the first terminal of the resistor R16 through the multiplexer MUX9 and the multiplexer MUX10, wherein at this time the coupling relationship among the resistors R11˜R16 is the connection in series.
The resistor switching array circuit of the first impedance 420 determines the coupling relationship among the resistors R11˜R16 through the control signals A0˜A4. An equivalent resistor Reqiv of the first impedance 420 is expressed by Reqiv=R11?(R12?(R13?(R14?(R15?R16)))), wherein “?” represents the connection in series or the connection in parallel (which is determined by the control signals A0˜A4 output by the controller 800. For instance, in the example illustrated in
For instance, with reference to
Taking the first impedance 420 illustrated in
The controller 800 may be a counter circuit or any other circuit. With reference to
In step S530, whether the impedance RITO2 of the sense lines is changed may be checked. If the impedance RITO2 is not changed, step S520 is returned to. If the impedance RITO2 is changed, step S540 is performed. For example, when the driving circuit 110 is changed to scan/drive the second drive line from first drive line, a length (i.e., the impedance RITO2) of the sense lines may be changed as well. Since the impedance RITO2 is changed, step S540 is performed.
In step S540, may check whether touch units 122 of the touch panel 120 are sensed or not. If all the touch units 122 are sensed, the sensing operation of the touch panel 120 is completed for once. If there are still touch units 122 uncompleted, step S550 is performed. For example, when the driving circuit 110 at present selects to scan/drive the second drive line of the touch panel 120, the controller 800 plus 1 to the control signals in step S550 since there are still touch units 122 waiting for completing the sensing operation. That is, the control signals A4, A3, A2, A1 and A0 are respectively set as 0, 0, 0, 0 and 1. Therefore, the controller 800 may set/adjust the equivalent resistor Reqiv of the first impedance 420 as R11|(R12∥(R13∥(R14∥(R15+R16)))) so as to perform step S520 again. Accordingly, the sensing compensation circuit 130 may automatically adjust the input impedance of the negative impedance circuit 400 corresponding to dynamic change in the impedance RITO2 of the sense lines. Thereby, the sensing compensation circuit 130 may provide corresponding negative input impedance −Req for offsetting/compensating the impedance RITO2 of the sense lines in spite of how the impedance RITO2 of the sense lines is changed.
Although in the exemplary embodiment illustrated in
A first terminal (e.g. a drain terminal) of the transistor M2 is coupled to the second input terminal of the amplifier 210. A second terminal (e.g. a source terminal) of the transistor M2 is coupled to the output terminal of the amplifier 210. A control terminal (e.g. a gate terminal) of the transistor M2 is coupled to a control voltage Vc2. The MOSFET M2 is controlled by the control voltage Vc2 and thus, may be served as a voltage-controlled resistor. A resistance of the second impedance 930 may be adjusted by determining a voltage level of the control voltage Vc2.
A first terminal (e.g. a drain terminal) of the transistor M3 is coupled to the second input terminal of the amplifier 210. A second terminal (e.g. a source terminal) of the transistor M3 is coupled to a reference voltage (e.g. a ground voltage). A control terminal (e.g. a gate terminal) of the transistor M3 is coupled to a control voltage Vc3. The MOSFET M3 is controlled by the control voltage Vc3 and thus, may be served as a voltage-controlled resistor. A resistance of the third impedance 940 may be adjusted by determining a voltage level of the control voltage Vc3. Since the equivalent input impedance Req of the negative impedance circuit is expressed by Req=−(R1R3)/R2, and thus, the negative input impedance −Req of the negative impedance circuit may be determined by adjusting the resistance (i.e., R1) of the first impedance 920, a resistance (i.e., R2) of the second impedance 930 and/or a resistance (i.e., R3) of the third impedance 940.
With reference to
A first terminal of the transistor J2 is coupled to the second input terminal of the amplifier 210. A second terminal of the transistor J2 is coupled to the output terminal of the amplifier 210. A control terminal (e.g. a gate terminal) of the transistor J2 is coupled to control voltage Vc2. The transistor J2 is controlled by the control voltage Vc2 and thus, may be served as a voltage-controlled resistor. A resistance of the second impedance 1030 may be determined by determining a voltage level of the control voltage Vc2.
A first terminal of the transistor J3 is coupled to the second input terminal of the amplifier 210. A second terminal of the transistor J3 is coupled to a reference voltage (e.g. a ground voltage). A control terminal (e.g. a gate terminal) of the transistor J3 is coupled to a control voltage Vc3. The transistor J3 is controlled by the control voltage Vc3 and thus, may be served as a voltage-controlled resistor. A resistance of the third impedance 1040 may be determined by determining a voltage level of the control voltage Vc3.
With reference to
A first terminal of the inductor L2 is coupled to the second input terminal of the amplifier 210. A second terminal of the inductor L2 is coupled to the output terminal of the amplifier 210. A control terminal of the inductor L2 is coupled to the control voltage Vc2. The inductor L2 is controlled by the control voltage Vc2 and thus, may be served as a voltage-controlled inductor. An inductance (an impedance) of the second impedance 1230 may be adjusted by determining the voltage level of the control voltage Vc2.
A first terminal of the inductor L3 is coupled to the second input terminal of the amplifier 210. A second terminal of the inductor L3 is coupled to a reference voltage (e.g. a ground voltage). A control terminal of the inductor L3 is coupled to control voltage Vc3. The inductor L3 is controlled by the control voltage Vc3 and thus, may be served as a voltage-controlled inductor. An inductance (an impedance) of the third impedance 1240 may be adjusted by determining the voltage level of the control voltage Vc3. Since the equivalent input impedance Req of the negative impedance circuit is expressed by Req=−(R1R3)/R2, the negative input impedance −Req of the negative impedance circuit may be determined by adjusting the impedance (i.e., R1) of the first impedance 1220, the impedance (i.e., R2) of the second impedance 1230 and/or the impedance (i.e., R3) of the third impedance 1240.
With reference to
A first terminal of the capacitor C2 is coupled to the second input terminal of the amplifier 210. A second terminal of the capacitor C2 is coupled to the output terminal of the amplifier 210. A control terminal of the capacitor C2 is coupled to control voltage Vc2. The capacitor C2 is controlled by the control voltage Vc2 and thus, may be served as a voltage-controlled capacitor. A capacitance (an impedance) of the second impedance 1330 may be adjusted by determining the voltage level of the control voltage Vc2.
A first terminal of the capacitor C3 is coupled to the second input terminal of the amplifier 210. A second terminal of the capacitor C3 is coupled to a reference voltage (e.g. a ground voltage). A control terminal of the capacitor C3 is coupled to the control voltage Vc3. The capacitor C3 is controlled by the control voltage Vc3 and thus, may be served as a voltage-controlled capacitor. A capacitance (an impedance) of the third impedance 1340 may be adjusted by determining the voltage level of the control voltage Vc3. Since the equivalent input impedance Req of the negative impedance circuit is expressed by Req=−(R1R3)/R2, the negative input impedance −Req of the negative impedance circuit may be determined by adjusting an impedance (i.e., R1) of the first impedance 1320, an impedance (i.e., R2) of the second impedance 1330 and/or an impedance (i.e., R3) of the third impedance 1340.
The sensing compensation circuit 130 may automatically adjust the compensation-impedance of the sensing compensation circuit 130 according to touch information of the sensing circuit 140 or a physical feature of the touch panel 120. For instance,
With reference to
After completing step S520, step S530 follows. In step S530, whether the impedance RITO2 of the sense lines is changed may be checked. For example, the sensing compensation circuit 130 may infer whether the impedance RITO2 of the sense lines is changed according to the touch information of the sensing circuit 140. Alternatively, the sensing compensation circuit 130 may infer whether the impedance RITO2 of the sense lines is changed according to driving operations of the driving circuit 110 on different drive lines. If the impedance RITO2 is not changed, step S520 is returned to. If the impedance RITO2 is changed, step S540 performed. For example, when the driving circuit 110 is changed to scan/drive the second drive line from first drive line, a length (i.e., the impedance RITO2) of the sense line may be changed as well. Since the impedance RITO2 is changed, step S540 is performed.
In step S540, may check whether touch units 122 of the touch panel 120 are sensed. If all the touch units 122 are sensed, the sensing operation of the touch panel 120 is completed for once. If there are still touch units 122 uncompleted, step S550 is performed to correspondingly adjust the compensation-impedance of the sensing compensation circuit 130. For example, when the driving circuit 110 at present selects to scan/drive the second drive line of the touch panel 120, the sensing compensation circuit 130 may change to set/adjust the compensation-impedance of the negative impedance circuit from a first resistance level to a second resistance level in step S550 since there are still touch unit 122 waiting for completing the sensing operation, such that step S520 is performed.
Accordingly, the sensing compensation circuit 130 may automatically adjust the compensation-impedance thereof correspondingly to dynamic change in the impedance RITO2 of the sense lines. Thereby, the sensing compensation circuit 130 may provide the corresponding negative input impedance −Req for offsetting/compensating the impedance RITO2 of the sense lines in spite of how the impedance RITO2 of the sense lines is changed.
In light of the foregoing, the disclosure introduces that the sensing compensation circuit 130 with negative resistance features may be used as a load of a sensing terminal of the touch panel 120, such that the limitations of the bandwidth resulted from the parasitic resistance (e.g. the impedance RITO2) and the parasitic capacitance (e.g. Cs2) of the sense lines may be reduced, the sensitivity for the entire sensing compensation circuit 130 sensing change of a mutual capacitance Cm may be enhanced, and thereby the SNR of the sensing signal may be increased.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
Claims
1. A touch device, comprising:
- a touch panel;
- a sensing compensation circuit, coupled to the touch panel and providing a compensation-impedance according to features of the touch panel; and
- a sensing circuit, coupled to the sensing compensation circuit and receiving touch information compensated by the sensing compensation circuit.
2. The touch device according to claim 1, wherein the sensing circuit comprises an integrator, an analog-to-digital converter and a controller.
3. The touch device according to claim 1, wherein a sensing terminal of the sensing compensation circuit is coupled to a sense line of the touch panel, and an output terminal of the sensing compensation circuit is coupled to an input terminal of the sensing circuit to sense touch information of a touch unit coupled to the sense line in the touch panel.
4. The touch device according to claim 1, wherein the compensation-impedance is a negative input impedance.
5. The touch device according to claim 1, wherein the compensation-impedance is a negative input impedance, and an absolute value of the negative input impedance falls within an impedance range defined according to an impedance of a sense line of the touch panel.
6. The touch device according to claim 1, wherein the compensation-impedance is a negative input impedance, and an absolute value of the negative input impedance is equal to an impedance of a sense line of the touch panel.
7. The touch device according to claim 1, wherein the sensing compensation circuit comprises:
- a negative impedance circuit, having an input terminal coupled to the touch panel and an output terminal providing touch information of a touch unit of the touch panel, wherein the input terminal of the negative impedance circuit provides a negative input impedance.
8. The touch device according to claim 7, wherein the sensing compensation circuit further comprises:
- a buffer, having an input terminal coupled to the output terminal of the negative impedance circuit.
9. The touch device according to claim 7, wherein the negative impedance circuit comprises:
- an amplifier, having a first input terminal coupled to the input terminal of the negative impedance circuit and an output terminal coupled to the output terminal of the negative impedance circuit;
- a first impedance, having a first terminal and a second terminal respectively coupled to the first input terminal and the output terminal of the amplifier;
- a second impedance, having a first terminal and a second terminal respectively coupled to a second input terminal and the output terminal of the amplifier; and
- a third impedance, having a first terminal and a second terminal respectively coupled to the second input terminal of the amplifier and a reference voltage.
10. The touch device according to claim 9, wherein one of the first impedance, the second impedance and the third impedance is a first impedance unit, a second impedance unit, a third impedance unit or a fourth impedance unit, wherein
- the first impedance unit comprises: a resistor, a variable resistor, a capacitor, a variable capacitor, an inductor or a variable inductor;
- the second impedance unit comprises: a plurality of switches, wherein first terminals of the switches are jointly coupled to the first input terminal of the amplifier; and a plurality of resistors, wherein first terminals of the resistors respectively coupled to second terminals of the switches in a one-to-one manner, and second terminals of the resistors are jointly coupled to the output terminal of the amplifier;
- the third impedance unit comprises: a transistor, having a first terminal coupled to the first input terminal of the amplifier and a second terminal coupled to the output terminal of the amplifier; and
- the fourth impedance unit comprises: a plurality of controllable resistance units, wherein a first terminal of a nth controllable resistance unit in the controllable resistance units is coupled to a second terminal of a n−1th controllable resistance unit in the controllable resistance units, a first terminal of a first controllable resistance unit in the controllable resistance units is coupled to the first input terminal of the amplifier, and third terminals of the controllable resistance units are jointly coupled to the output terminal of the amplifier; and a first resistor, a first terminal of the first resistor is coupled to a second terminal of the last controllable resistance unit in the controllable resistance units, and a second terminal of the first resistor is coupled to the output terminal of the amplifier.
11. The touch device according to claim 10, wherein one of the controllable resistance units comprises:
- a second resistor, having a first terminal served as the first terminal of the controllable resistance unit;
- a first multiplexer, having a common terminal coupled to a second terminal of the second resistor, and a first select terminal served as the third terminal of the controllable resistance unit; and
- a second multiplexer, having a first select terminal coupled to the first terminal of the second resistor, a second select terminal coupled to a second select terminal of the first multiplexer, and a common terminal of the second multiplexer served as the second terminal of the controllable resistance unit.
12. The touch device according to claim 7, wherein the negative impedance circuit is a first negative impedance circuit, a second negative impedance circuit or a third negative impedance circuit, wherein
- the first negative impedance circuit comprises: an amplifier, having a first input terminal coupled to the input terminal of the negative impedance circuit, and an output terminal coupled to the output terminal of the negative impedance circuit; a first transistor, having a first terminal and a second terminal respectively coupled to the first input terminal and the output terminal of the amplifier; a second transistor, having a first terminal and a second terminal respectively coupled to a second input terminal and the output terminal of the amplifier; and a third transistor, having a first terminal and a second terminal respectively coupled to the second input terminal of the amplifier and a reference voltage;
- the second negative impedance circuit comprises: an amplifier, having a first input terminal coupled to the input terminal of the negative impedance circuit and an output terminal coupled to the output terminal of the negative impedance circuit; a first variable inductor, having a first terminal and a second terminal respectively coupled to the first input terminal and the output terminal of the amplifier; a second variable inductor, having a first terminal and a second terminal respectively coupled to a second input terminal and the output terminal of the amplifier; and a third variable inductor, having a first terminal and a second terminal respectively coupled to the second input terminal of the amplifier and a reference voltage; and
- the third negative impedance circuit comprises: an amplifier, having a first input terminal coupled to the input terminal of the negative impedance circuit and an output terminal coupled to the output terminal of the negative impedance circuit; a first variable capacitor, having a first terminal and a second terminal respectively coupled to the first input terminal and the output terminal of the amplifier; a second variable capacitor, having a first terminal and a second terminal respectively coupled to a second input terminal and the output terminal of the amplifier; and a third variable capacitor, having a first terminal and a second terminal respectively coupled to the second input terminal of the amplifier and a reference voltage.
13. The touch device according to claim 12, wherein the first negative impedance circuit further comprises:
- a first resistor, having a first terminal and a second terminal respectively coupled to the first terminal and a control terminal of the third transistor; and
- a second resistor, having a first terminal and a second terminal respectively coupled to a control voltage and the control terminal of the third transistor.
14. The touch device according to claim 1, wherein the sensing compensation circuit comprises:
- a controller; and
- a negative impedance circuit, having an input terminal coupled to a sense line of the touch panel to provide the compensation-impedance, wherein the controller controls the negative impedance circuit to correspondingly adjust the compensation-impedance according to the touch information of the sensing circuit or a physical feature of the touch panel.
15. The touch device according to claim 14, wherein the touch information of the sensing circuit is a coordinate axis, a digital signal or an analog signal.
16. The touch device according to claim 14, wherein the physical feature comprises electrical features of the touch panel or change in the electrical features of the touch panel resulted from change of panel type, temperature or humidity change of an environment where the touch panel is located.
17. The touch device according to claim 1, wherein the sensing compensation circuit comprises:
- a multiplex circuit, having a plurality of select terminals respectively coupled to a plurality of sense lines of the touch panel in a one-to-one manner; and
- a negative impedance circuit, having an input terminal coupled to a common terminal of the multiplex circuit to provide the compensation-impedance.
18. A sensing compensation method for a touch device, comprising:
- providing a touch panel;
- providing a compensation-impedance by a sensing compensation circuit according to features of the touch panel; and
- receiving touch information by a sensing circuit, and the touch information being compensated by the sensing compensation circuit.
19. The method according to claim 18, further comprising:
- sensing a sense line of the touch panel by the sensing circuit through a sensing terminal of the sensing compensation circuit to obtain touch information of a touch unit coupled to the sense line in the touch panel.
20. The method according to claim 19, wherein the step of providing the compensation-impedance comprises:
- providing a negative input impedance by the sensing terminal of the sensing compensation circuit to compensate an impedance of the sense line.
21. The method according to claim 20, wherein an absolute value of the negative input impedance falls within an impedance range defined according to the impedance of the sense line.
22. The method according to claim 20, wherein an absolute value of the negative input impedance is equal to the impedance of the sense line.
23. The method according to claim 18, wherein the step of providing the compensation-impedance comprises:
- correspondingly adjusting the compensation-impedance by the sensing compensation circuit according to the touch information of the sensing circuit or a physical feature of the touch panel.
24. The method according to claim 23, wherein the touch information of the sensing circuit is a coordinate axis, a digital signal or an analog signal.
25. The method according to claim 23, wherein the physical feature comprises electrical features of the touch panel or change in the electrical features of the touch panel resulted from change of panel type, temperature or humidity change of an environment where the touch panel is located.
26. The method according to claim 18, further comprising:
- checking whether an impedance of the sense line of the touch panel is changed;
- if the impedance of the sense line is changed, correspondingly adjusting the compensation-impedance.
Type: Application
Filed: Jan 24, 2014
Publication Date: Dec 25, 2014
Patent Grant number: 9766749
Applicant: Industrial Technology Research Institute (Hsinchu)
Inventors: Yen-Lin Pan (Kaohsiung City), Wei-Yen Lee (Taichung City), Chang-Po Chao (Taipei City), Hung-Ming Tsai (Taichung City), Hsuan-Wen Peng (Miaoli County)
Application Number: 14/162,781
International Classification: G06F 3/041 (20060101); G06F 3/045 (20060101); G06F 3/044 (20060101);